Originally reconstructed upside down, walking on stilt legs with wavy tentacles on her back (Conway Morris, 1977), Hallucigenia later received a more plausible reconstruction upon further examination of extinct relatives (Ramskold & Xianguang, 1991). However, her head eluded confused primates for decades to come. The only clue was a blobby thingy at one end of her body. Fortunately, new specimens and the rise of the machines later revealed her head, complete with simple eyes, mouth, and pharyngeal teeth, at the end opposite the blob (Smith & Caron, 2015). Turns out the blobby thingy was just decay fluid… Like her modern kin (velvet worms), she possesses Matryoshka doll style claws (and in her case, also spines) composed of layered chitin, the same carbohydrate that forms arthropod exoskeletons.

Possibly the largest land mammal of all time, rivaled only by Palaeoloxodon namadicus, the Asian straight-tusked elephant. Unlike modern rhinos, he prefers leaves to grass, since grass was not abundant yet.

On a more important note: PLEASE. STOP. KILLING. RHINOS. Rhino horns are no more than incredibly compressed hair (They are composed solely of keratin, the protein that forms hair, nails, claws, and tetrapod scales.) and will not cure any diseases, extend your life expectancy, nor boost your sex life.